Two general types of dialysis therapy are now in wide spread use. One type, hemodialysis provides for removing waste products by passing the blood of a patient through an appropriately constructed dialyzer unit. A second type of dialysis therapy, peritoneal dialysis, utilizes the membrane in a patient's peritoneal cavity for the purpose of separating waste products from the patient's fluid systems.
In one form of peritoneal dialysis, referred to as continuous ambulatory peritoneal dialysis (CAPD), dialysis fluid is introduced into the patient's peritoneal cavity by means of an in-dwelling peritoneal catheter. The dialysis solution is permitted to remain in the peritoneal cavity of the patient for a time interval on the order four to six hours. At the end of this time interval, spent fluid is drained from the patient's cavity, under the influence of gravity, and fresh dialysis fluid is infused into the cavity to continue the process.
The drain and fill cycle noted above is carried out best where the patient systematically executes a predetermined sequence of steps to first drain spent fluid and then to refill the peritoneal cavity with fresh fluid. Carrying out the predetermined sequence of steps requires opening and closing, in a predetermined sequence, a plurality of flexible tubing members in a fluid flow transfer set connected between the external end of the patient's catheter and solution containers of peritoneal dialysis fluid.
One valve system useable in carrying out this procedure is illustrated in U.S. Pat. No. 4,239,041 to Popovich et al. entitled "Method For Continuous Ambulatory Peritoneal Diaylsis." The valve system of the Popovich et al. patent is integrally formed with the transfer set disclosed therein. The transfer set including the valve system is of a type that would be worn by the patient for an extended period of time.
Since the Popovich et al. valve system is intended to be carried about the patient's person, it of necessity must be formed to be relatively small and light weight. Hence, there are substantial limits as to the mechanical advantage that can be obtained with such a structure. The Popovich et al. valve system must also be formed out of material that can be sterilized during the manufacturing process of the set. In addition, the Popovich et al. valve system must be formed of material which is suitable for long term patient contact and which can be periodically flushed with disinfectant solution.
U.S. Pats. Nos. 4,425,113 and 4,428,745 issued respectively to Bilstad and Williams disclose several mechanical fluid flow control valves for use with fluid transfer sets. These valves are formed with a base into which can be placed a portion of the transfer set. A hinged top, attached to the base can then be closed over the base. A moveable flow control member attached to the top can be used to close various of the fluid flow conduits that extend into the base. The disclosed valves are illustrated in connection with transfer sets usable for plasma pheresis.
There thus contains to be a need for a valve system and related set which provides reasonable mechanical advantage to the patient while opening and closing the fluid flow conduits of the set. In addition, there continues to be a need for a valve system which is reusable and which can readily be utilized with single use transfer sets without compromising the sterile or aseptic condition of the internal lumens of the fluid flow conduits of the set.